Various types of metering devices are known. One example is the electronic postage meter as, for instance, described in U.S. Pat. No. 3,978,457 to Check et al. As is well known, postage meters include an ascending register, that stores a running total of all postage dispensed by the meter, and a descending register, that holds the remaining amount of postage credited to the meter and that is reduced by the amount dispensed each time postage is printed by the meter. Because U.S. Postal Service regulations require that postage be paid in advance, it had traditionally been required that the user of a postage meter periodically present the meter to a Postal Service employee for recharging. At the time of recharging, the user paid to the Postal Service the amount of postage to be credited to the meter and the postal employee credited or recharged the meter by increasing the setting of the descending register by the amount paid. As the meter was used to dispense postage (by printing meter stamps on envelopes or labels), the setting of the descending register was reduced until either the meter was again recharged, or the setting reached zero or a pre-established figure near zero, at which point the meter was automatically locked, and thereby prevented from printing further meter stamps, until the meter was recharged. This locking feature is sometimes referred to as a "credit lockout", signifying that the meter is disabled upon exhaustion of the previously credited amount.
An improved and more convenient method of recharging postage meters while still satisfying Postal Service regulatory requirements has been developed and is described, for example, in U.S. Pat. No. 3,792,446 to McFiggins, et al., entitled "Remote Postage Meter Resetting Method". As described in the McFiggins, et al. patent, a postage meter includes a combination lock that inhibits recharging of the meter. The required combination randomly changes each time the lock is opened. The user of the postage meter maintains an account with a credit balance. A central data center maintains a record of the user's account. When the user wishes to recharge the meter, he places a telephone call to the data center. The data center, using a voice answer back system, obtains identifying information from the user, verifies the information and checks to see that the user has sufficient funds in his account to cover the postage to be credited to the meter. The data center then provides a combination to the user that will allow the meter to be credited with a pre-determined amount of postage. At the same time, the center debits that amount from the user's account. The user enters into the postage meter the combination received from the data center. The meter is then unlocked so that the user can increment the descending register by the predetermined amount.
The remote recharging method described by McFiggins et al. was implemented with great success. A subsequent adaptation and improvement of this method is described in U.S. Pat. No. 4,097,923 to Eckert et al. The system of Eckert et al. is operable with a micro-computer controlled postage meter and allows the user to select a variable amount of postage with which the meter is to be credited. In the Eckert et al. system the user advises the data center of the selected amount of postage and the data center provides a combination that reflects the selected amount of postage. The user enters the selected amount and the combination into the meter, which makes its own calculation of a combination based upon the entered amount. The calculated combination is compared to the entered combination and if the two are consistent, the descending register is incremented by the entered amount.
In contrast to the U.S. Postal Service, the postal authorities of some foreign countries do not require prepayment of postage in all cases. In those countries, postage meters are not required to have the credit lockout feature. Postage meters of the type previously described herein may be adapted for use in those countries by, for example, eliminating the mechanism that locks the meter when the descending register reaches its minimum reading, or by omitting the descending register entirely, or by setting the descending register to a very high reading, or by allowing the user to reset the descending register whenever necessary. However, since postage is not prepaid, arrangements must be made for payment after the fact. Typically these arrangements include presentation of the meter for reading by a postal employee with payment in response to billing based on the meter reading. There is considerable inconvenience in carrying the meter to a post office for reading, or in dispatching a postal employee to the user's office.
Inconvenience in meter reading is not confined to postage meters used in post-payment countries. For example, conventional utility meters, such as gas, water or electric meters also are read by a utility company employee. Although some utility companies require their customers to read the meter and to mail in a reporting card with the current reading, accuracy of the customer's reports still must be periodically verified by sending an employee to read the meter. With or without interim reports from customers, the utility incurs the expense of maintaining a force of meter readers.
It has been proposed to obtain meter readings via telecommunications, as for example in: U.S. Pat. No. 4,833,618 to Verma et al., entitled "System for Automatically Reading Utility Meters from a Remote Location"; U.S. Pat. No. 4,878,245 to Bradley et al., entitled "Control and Metering System for Pay Television over a Cable Network." However, the addition of telecommunication receiving and transmitting equipment to the meter would add significantly to the cost of manufacturing a meter. Also, and particularly in the case of utility or postage meters, attachment to the meter of a dedicated but rarely used telephone line would entail substantial additional operating costs.